"His parent is a teacher" is wrong? His or her can not be distinguished, correct?
Professions are gendered in a stereotypical way (she is murse, he is carpenter)
That's not an explanation why "her parent is a teacher" is accepted but "his parent is a teacher" is not. The gender isn't regarding the teacher but the undefined child of the teacher.
And at the same time you are suggesting that one cannot say "he is a nurse" in Swahili?
There is a concept of classes which the nouns should belong. Also, possessive pronouns, adjectives etc have to agree with the class of the noun. For example, here "mzazi" belongs to the m - wa class , so the possessive has to be "wangu" to agree with the class of mzazi for the corresponding English "my".
If the example had been "My book ... ", the Swahili would have been "Kitabu changu ..." and "My books ..." would be "Vitabu vyangu ..." . Notice the pattern. I hope that helps.
I did find this out later yes, thank you! But there are words that belong to the m - wa class, which stem from Arabic, that get the y- prefix right? Like dada or kaka. Are there any other exceptions?
I wouldn't say that dada and kaka are in the M/WA class, since their singular and plural forms are identical, and they agree with verbs like N/N nouns. Wiktionary says "dada (n class, plural dada)". I find it weird that they don't get M/WA agreement on the basis of being animate (N/N animals do), but that's the way it is.
Also, not all Arabic-derived words for people are like this; mwalimu comes from Arabic! (It's probably helped by the fact that the original Arabic verb starts with mu-, so it's a pretty short step for Swahili to reanalyze the Arabic form II active participle as having an M/WA prefix, especially since it describes a person. A similar thing happens with kitabu, where the k is an integral part of the Arabic root, but in Swahili it becomes part of the prefix.)
Asante sana! I believe I saw them listed under the M-WA class somewhere, but it makes much more sense that they are in the N/N class instead. Yea me too.. but indeed, you cannot argue with language. It is the way it is.
Okay good to know!